Compression-reducing device for internal-combustion engines



Y K. ELTZE 1,789,036

COMPRESSION REDUCING DEVICE FOR INTERNAL COMBUSTION ENGINES Jan. 13, 1931.

Filed Dec. 20, 1928 Jarm/ar:

Patented 3a.. 13, 193i UNITED "STATES? PATENT OFF-ICE KURT ELTZE, F MANNHEIM-KAFERTAL',

MANY g V comrnnssxon-nnnucme nEvIcE non :rn'rnmvan-comnnsrion ENGINE-S1- 1 Application filedDecemberQO, 1928, Serial No. 327,439, and a Germany January 9,

The starting of internal combustion en gmes, more particularly of oil engines in which the fuel is injected without the aid operation for multi-cylinder engines. by' changing, over onecylinder after the other .to operate on full compression pressure by of compressed air, is particularly difficult owing to the high compression pressures;

It has already'been proposed tosimplify the automatic displacement; of the v cam shaft.

A second method on which the present in-" vention is also based consists in this, that theengine is first offall turned round without any compression whatever, that is to say with. open inlet and exhaust valves, the

engine beingthen changed over to operate on a low, compression and some fuel is ad-' mitted, the: ignition being initiated by means of the known'auxiliary devices, such as nitrated touch paper or electric sparking plugs. By a further changeover the en g ne passes over to normal operation withj full compression. V

In this connection therefis thedifficulty "that the operatorat the moment'in which he is occupied in turning over the engine, has to displace thecam shaft by hand for efi'ecting the change over to the reduced compression pressure. This drawback. is re'- moved according to the present invention by causing the first adjustment of the cam shaft, that is to say. for efiecting the change over of the engine'from operation with open inlet and exhaust valves tooperation with reduced compression, to take place auto,- matically. The second displacement ofthe camshaft when changing over from the reduced compression to full compression is then effectedby hand. This does 'not cause any diflicultiesfsince with the changeover to reducedcompression, fuel is already being applied and ignitions take place.

A constructional form of the compression reducing device according to the invention is illustrated by way ofexample in the ac companying drawing, in which 'F 1 is a longitudinal ele vation in part section show- @ing the position "occupied by: the cam 5 shaft at the commencement of starting, that is to GERMANY, ASSIGNORV TO DAIMLER-BENZ AKTIENGESELLSCHAIT; Fs U'rTGAR r-BERLIN, GERMANY; A COMPANY or, ennsay when w the {inlet and exhaust' valves 1 are held open.

7 "Fig. 2 is an enlargedlongitudinal section- "1. a1 view of -th'e compressionreducingdevice; 1

and

2, showing the shaft projection.

.47. Fig. 3 s a transverse sect onal viewof Fig.

plat-e opening forthecam Referring to the drawing, a Q

is under the action of a spring 'b which tends to displace it towards the right and against the bushing da'nd the cover-e. The bushing d is rotatably mounted in the sleeve f which is screwedinto the wall of themotor'casing" by means of a quickscrew thread. The end of the bushing d which. faces the cam shaft is turned'out and the cavity thus formed is I closed by means of the screwed on' cover e g' A prolongation of the cam shaftfa passes into a bore inlfthe disc e. v ()n the said pro longation is provided the projection c'by means of which thec'am shaft a is supported upon the' cover 6, being pressed 4 against the same by means of the spring I). The projection 0 is ca'pableof passing. through a slot in the cover 6.

At the'commenceme'nt of starting up, the i engine is brought intothe position wherein I the projection 0 has alreadypassed the slot 1n the cover e in the direction of rotation.

In, the case of a fourcycle engine, thei' proje'c'tion will pass through the slotafter ape.

proximatelyone revolution of'the cam :shaftc or after two revolutions of the crank shaft.

Thecam shaft a then; slides under the action of the spring. b' towards the right until the prolongation strikes against the boss 2' of the 7 pin iaj'In this position of the cam shaft,

the engine operates with reduced compres-' sion, some fuel being also supplied as olescribed morefully above. 7

In order to effect the change over to a full compression, the sleeve fr isl'screwed vout somewhat by hand by-means of ahandle g,

the cam shaft following underthe pressure of the springfb.

c If the engine is to be-startedagain after. havingfbeen'lstopped, then thestarting dewoe is put into operationjin. the following mannerz' By means ofthe pin it the cam.

- shaftis pressed against the action of the spring Z) to the left, until the projection 0 bears against the inner side, that is to say the right-hand side of the cover 6. The

bushing (Z is then turned until the slot in the cover 6 is in register withthepro'jection 0. As soon as the pro ect1on is passed through the slot the bushing d is turned in he pposite di ctionhto. t e d rection: of-

at o the cam. sh t-a450 fargthatxthe projection 0 rests upon the cover 6. By

turning the sleeve 7 by means of the handle 9, the cam shaft is then moved still further towards the left into. the position shown in the drawing. Y What I claim is 1. 'A compression reducing device for recomhu'stion engines when [starting u'p the same, comprising 'the' combination with, a cam shaft capable of axial displacement" from a starting' position fto anormal running position,- and cam shaft displacing meansoperatively connected "to the cam' shaft and tending to urge the cam shaft from its sjtarting position' to its normal running position, of a stationary retainingdevice adapted to hold the cam shaft in its starting position and'to release the cam shaft after the latter has turned through a definite angle'of rotationgs'o as to enable the vcam shaft tomove'sunder the action of the said' displacing means ii1 to 'its normal running position. i

'2. A compression reducing device for reducing'the compression pressure of internal combustion engines when starting up the same, comprising the combination with camshaft capable of axial displacement from a starting, position to a normal running position and a cam shaft displacing means operatively connected to the cam shaft and tending to urge the cam shaft from its starting position to its normal running position, of a retaining device adapted'to hold the camshaft 'in its startin position and to release the'cam shaft afierthe' latterjhas turned through a definite angle of rotationand'anabutment adapted to engage'the cam shaft and hold it in a position intermediate of its starting'and normal running positions on the release of'the cam shaft by the said retaining device, said wabutment being capable of displacement by hand in the directi'on of the cam shaft axis so 'as'to enable the cam shaftto move from said intermediate position into its normal running position.

3. A compression reducing devicefor reducin 'the' compression pressure of internal combustion engines whenfistarting up the. same, comprising the combination'with a" cam shaft capableof displacement from a startin positiont'o a normal running position ant yielding camshaft displacing means operatively connected to the cam shaft and H tending to urge thecam shaft from its start- Whifih' the. camshaft is capable of. enteringon v, 133.. rel a e by sa d.retainmgi'means and an abutment in said bushing adapted to engage the cam shaft for holding the latter in a positioniintermediate of its starting and normal running positions, said abutment being 7 fdisplac'eableby-hand in-thedirection'of the cam shaftaxis so as toenable the cam shaft I tomovefrom-said intermediatepo'si'tion into duoing the compression pressure ofinternal" its normal running position.

L'A compression 'reduci duclng the compression pressure of internal combustion, 'enginesl'when starting up thesame, comprisingthe combination with a camshaft capable of displacement from a I starting position to anormal, running position "and y1eld1ngfcam shaft displac ng means operatively connectedfto, the cam,

shaft and tendingtofurge the cam shaft ng device for refrom its starting position to its normal run- 1 ning position, of a bushing mounted in the casing of the engineandhaving retaining means ada'ptedto hold the cam shaft in its starting position and to release the cam shaftafter the latter-hasturned through a 'definiteangle of rotation,"said bushing havment, heing displaeeahle by hand in the direction ofthe' shfaft a x is so as to enable the cam shaft'to move .f from' said intermediate position into fits'iiormal"running position. T f

5. A, compression reducing device for reducing the compression pressure of internal combustion engines when starting up the same, comprising the combination with a cam shaft capable .of displacement" from a llO starting position to .a normal running posie tion "andyielding cam shaft displacing" means operatively' connected to the cam shaft'a-nd tending to urge the cam shaft 7, from its starting position to its normal running pos1t1on,l of a sleeve having a quick screw thread screwed'into. the vwall of the ,engine casing and-shaving a-handle for enabling itto be turned by hand, a bushing in said sleeve and having acavity in oneend.

thereof facinghthe camshaft; a cover on said bushing over said cavityand'having an aperture therein, a prolongation on the cam a t: relef p s g ithrue s ep rstarting position to a normal running position and yielding cam shaft displacing means operatively connected to the cam shaft and tending to urge the cam shaft from its start- 7 5 ing position to its normal running position, of a sleeve having a quick. screw threadscrewed into the wall of the engine "casing ture into the said cavity, a projection on said prolongation adapted to support the cam shaft against said cover against the action of the yielding displacing means, a slot in said coverthrough which said projection can enter, said bushing being rotatable in the sleeve for enabling its angular position to be adjusted with respect to said projection that the latter can enter the slot and allow the prolongation to pass through the cover into the cavity after the camshafthas turned through a definite angle, and an abutment in said bushing adapted to engage the said prolongation and hold the cam shaft in a position intermediate of its starting and normal running positions.

6. A compression reducing device for reducing the compression pressure of internal combustion engines when starting up the same, comprising the combination with a cam shaft capable of displacement from a and having a handle for enabling it to be turned by hand, a bushing in said sleeve and having a cavity in one end thereof facing the cam shaft, a cover on said bushing over said cavity and having an aperture therein, a prolongation on the cam shaft capable of passing through said aperturejnto the said cav1ty,a projection on said prolongation adapted to support the cam shaft against a said cover against the action of the yielding displacing means, a slot in said cover through which said projection can enter, said bushing being rotatable in the sleeve for enabling its angular position to be adjusted with respect to said projection that the latter can enter the slot and allow the prolongation to pass through the cover into the cavity after the cam shaft has turned through a definite angle, and a pin in said bushing adapted to engage the said prolongation and hold the cam shaft in a posi- 1 tion intermediate of its starting and normal running positions, said pln being slidable in said bushing and capable of'displacing their camshaft tora position with the projection on the prolongation outside said cover, so as to enable the cam shaft to be returned to its starting position. I

In testimony whereof I have signed my name to this specification.

KURT ELTZE. 

